How can I identify the apple tree variety in my backyard?
Determining the identity of an apple variety is difficult as there are hundreds of potential cultivars or varieties of which it could be. Iowa State University does not offer apple variety identification services. In most cases, the only way to know for certain what variety of apple you have is to have some form of documentation such as a plant label, receipt, letter, or journal entry from the gardener who planted the tree. Often this is not available as in many cases the person looking to identify the apple variety has recently purchased or inherited a property and was not made aware of the varieties of fruit trees growing on the property.
Sometimes you can narrow down the possibilities to a short-list of potential cultivars based on the color, texture, appearance, time of ripening, age, and size of the tree, but even that is an estimation and not a true identification. Some online apple cultivar databases, such as http://www.applename.com/, have interactive tools that allow you to create a short-list of potential cultivars and potentially identify what variety of apple you have or what variety it is most similar to.
If you enjoy the apple and want more trees or want to replace declining trees, rather than attempting to identify the variety and purchase new trees, it is best to propagate the apple tree yourself. Propagating the apple by grafting or cuttings allows you to get a new tree that is genetically identical to the parent plant. There are also nurseries that will graft scion wood you collect and send you ready to plant trees after a couple of years for a fee. Doing this means you will never know the true variety of the apple, but you will get to continue to enjoy it.
Finally, UC-Davis will accept samples for DNA fingerprinting on a fee-for-service basis. More information about the costs and material needed for this service is on their website. https://fps.ucdavis.edu//dnamain.cfm